Railway traffic controlling system



Oct. 26, 1937.

F. B. HITCHCOCK RAILWAY TRAFFIC CONTROLLING SYSTEM Filed May 10, 1935 2 Sheets-Sheet 1 FIG. 1.

I4 I L? L w H- -L Q 6 w Oct. 26, 1937. F. B. HITCHCOCK RAILWAY TRAFFIC CONTROLLING SYSTEM 2 Sheets-Sheet 2 Filed May 10, 1935 u .w cm mm lm P 55 i .A 1

FIG. 3.

Signal CircuiT selecfions Patented Oct. 26, 1937 UNITED STATES PATENT OFFlQE Forest B. Hitchcock, Greece, N. Y., assignor to General Railway Signal Company, Rochester,

Application May 10, 1935, Serial No. 20,795

18 Claims.

This invention relates to traffic controlling systems for railroads, and more particularly pertains to the indication of the position and locked condition of power operated track switches employed in railroad interlocking systems.

The present invention proposes to provide a novel system for indicating the position and locked condition of a railway track switch over a polarized indication circuit in a manner more reliable than has been heretofore accomplished. In brief, the present invention provides that a polar-neutral relay is energized over a polarized circuit with one polarity or the other depending upon the position of the railway track switch or is deenergized whenever the track switch is unlocked. Such control, however, is provided in a manner that the response of the polar contacts of such polar-neutral relay is required in order for the neutral contacts of such relay to remain in picked up positions throughout the energize.-

tion of such polarized circuit. Such dropping away of the neutral contacts of the indication relay in the event of the failure of its polar contacts to respond, prevents the improper clearing of signal for the passage of traflic.

Various other features, advantages and characteristic functions of the present invention will be in part apparent from the accompanying drawings and in part pointed out as the description thereof progresses. I

In describing the invention in detail, reference will be made to the accompanying drawings in which:

Fig. 1 illustrates in a simplified and diagrammatic manner one form of the present invention applied to a railroad track switch and the signals governing traiiic thereover;

Fig. 2 illustrates in a diagrammatic and simplified manner a second form of the present in- 49 vention; and

Fig. 3 illustrates in a simplified and diagrammatic manner a third form of the present invention.

With reference to the accompanying drawings, the invention has been shown applied to a single railroad track switch, although it is to be understood that the invention may be employed with a crossover, or any other track layout combination that may be encountered in actual practice.

With more specific reference to Fig. 1, a track switch is shown as operated by a suitable switch machine SM, which switch machine may be of any suitable type such as disclosed, for example, in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923.

Associated with the track switch TS and the switch machine SM is a point detector contact mechanism PD which includes movable contacts 3 and 4. This point detector contact mechanism PD may be of any suitable type, such for example, as shown in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924. Although the contacts 3 and 4 are jointly operated by the track switch TS and switch machine SM through the point detector contact mechanism PD as shown in detail in the abovementioned patent, it is believed to be sufficient for an understanding of the present invention to know that the contacts 3 and 4 are in their present normal positions when the track switch TS is in a normal position in correspondence with the switch machine SM and is locked; that the contacts 3 and 4 are in dotted line mid-positions whenever the track switch TS is unlocked or is in operation; and that the contacts 3 and 4 are in reverse dotted line positions whenever the track switch TS is in a reverse position in correspondence with the switch machine SM and is locked.

The switch machine SM is indicated as controlled by a suitable switch machine control lever SML located in a central ofiice or tower, which control may be of any suitable type such as shown, for example, in the pending application of R. M. Phinney Ser. No. 539,486, filed May 23, 1931.

The track switch TS is illustrated as having signals lA--|B and 2A-2B for governing trafiic thereover. The signals 5A and IB govern east bound traffic over the track switch in normal and reverse positions respectiveiy; while the sig nals 2A and 2B govern West bound traflic over the track switch in normal and reverse positions respectively.

Preferably associated with the track switch TS is the usual detector track section having a battery and the usual track relay, as well as various other adjuncts of a signalling system. But all of these adjuncts and usual features of traffic controlling systems have been omitted for the sake of simplifying the disclosure of the present invention.

In the central office or tower, a. suitable polar neutral relay WP, such as disclosed, for example, in the Patent No. 1,749,331 dated March 4, 1930, is associated with the switch machine control lever SML and a signal control lever SGL for the purpose of providing contacts repeating the position and locked condition of the track switch TS, which contacts may be used to select the circuits for the signals lA-lB and 2A2B as well as for the purpose of selecting various locking circuits and the like in accordance with the usual practices. A slow acting neutral type relay CK is associated with the relay WP for reasons later to be explained in detail.

Although the signal lever SGL is indicated as controllin only the signals 2A and 2B, it is to be understood that control circuits for signals IA and EB may be similarly provided.

The relay WP and its checking relay CK are considered as located in the central office, but it should be understood that they may be located at any suitable point for the purpose of accomplishing to the best advantage the selections for which they are provided. Also, the principles of the present invention as embodied in the control of the relays WP and CK may be employed in other connections than for the purpose of indicating the position and locked condition of a railroad track switch, for which indication purposes it is particularly suited.

It is also to be understood of course, that any number of contacts may be provided on the relays WP and CK to accomplish the selections required. These relays WP and CK may also control indicator lamps for indicating when the track switch TS is unlocked and also when the track switch is locked in normal or reverse positions. The control of the relays CK and WP in Fig. 3will also permit the control of a correspondence lamp. Such indicator means has not been shown in the present disclosure because it is believed that such means may be readily added in accordance with the particular situation in which the present invention is employed.

Figs. 2 and 3 illustrate only those parts of the system shown in Fig. 1 which are modified. In

other words, the same control of the track switch TS is contemplated although the switch machine and its connection with the control lever SML has not been indicated. Also, the signal circuits may be selected as shown in Fig. 1, although this has been merely indicated by a legend.

The same reference characters have been employed in Figs. 2 and 3 as in Fig. l with regard to the devices which are the same, but those circuit connections which differ from Fig. 1 have been provided with distinctive reference characters on the contacts included therein in order to distinguish such circuits in the description.

For the purpose of energizing the switch repeating relay WP and the checking relay CK over line wires 5 and 6, a suitable battery BT has been illustrated, but it is to be understood that any suitable source may be provided for energizing the line circuit. Certain other sources of energy are indicated in the drawings by suitable symbols instead cf showing the actual connections to such sources. The symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries, or other sources of direct current; and the circuits with which these symbols are used, always have current flowing in the same direc tion. The symbols (B+) and (B) indicate connections to the opposite terminals of a suitable battery, or other direct current source which has a central or intermediate tap designated (CN) and the circuits with which these symbols are used, may have current flowing in one direc tion or the other depending upon the particular terminal used in combination with the intermediate tap (CN).

In Fig. 1, suitable asymmetric units it, il, [8 and 19 are provided in connection with the re lay WP having their low resistance directions as indicated by the arrow heads for purposes hereinafter more specifically set forth. These asymmetric units it, ii, iii and it may be of any suitable type, but for the purposes contemplated in accordance with the present invention suitable copper oxide rectifier discs may be very advantageously employed.

It is believed that the nature of the invention, its advantages and characteristic features can best be understood with further description being set forth from the standpoint of operation.

Operation With more particular reference to Fig. l of the accompanying drawings, the track switch TS is considered to be in correspondence with'the switch machine SM in a normal locked position and also to be in correspondence with its control lever SML. Under such conditions, the point detector contact mechanism PD causes the contacts 3 and l to be in their normal positions as shown, thereby supplying energy to the line wires 5 and 5 from the battery BT, which causes the energization of the checking relay CK and the switch position indicating relay WP.

More specifically, the relay CK is energized by a circuit closed from the positive terminal of battery ET, through a circuit including contact 3 of the point detector contact mechanism in the normal position, line wire 5, winding of relay CK, line wire 6, contact of the point detector contact mechanism a normal position, to the negative terminal of the battery BT.

In multiple with the relay CK and across the line wires 5 and 6 is connected the normal stick circuit of the relay WP. More specifically, this circuit is closed from the line wire 5, through a circuit including front contact 52 of relay CK, front contact 9 of relay WP, asymmetric unit l6, polar contact l of relay WP in a righ hand position, lower winding of relay WP, polar contact 8 of relay WP in a right hand position, asymmetric unit 29, to the line wire 6.

The energy which flows in this normal stick circuit of relay WP in multiple with the reiay CK causes the neutral contacts of the relay WP to remain picked up continues to actuate the polar contacts to their right hand positions, as initially accomplished through its pick-up or operating circuit shortly to be pointed out in detail.

With the relays WP and CK picked up, as shown, the signal 2A may be cleared upon the actuation of the signal iever SGL to the left closing a circuit from through a circuit including lever SGL in a left hand position, front contact [3 of relay CK, front contact iii of relay WP, polar contact I! of relay WP in a right hand position, line wire 54, signal mechanism 2A, to

It might be noted in this connection that with the track switch TS in a reverse position so that the point detector contacts 3 and e are actuated to their reverse positions causing the relay WP to actuate its polar contacts to reverse positions, the signal 23 may be energized over line wire l5 upon the actuation of the. signal lever SGL to its left hand position by reason of contact if being in a left hand position. The signais IA and EB may be similarly controlled upon the actuation detector contact mechanism 1n a reverse position,

.of the lever SGL to the right but such circuits have been omitted for the sake of simplicity.

, Assuming that the signals governing trafiic over the track switch are at stop and that the operator moves the lever SML to a right hand reverse position, then the switch machine SM unlocks the track switch TS and operates it to a reverse locked position. While the track switch TS is unlocked and is in midstroke, the contacts 3 and 4 are in their center positions causing the line wires 5 and 6 to be shunted by a circuit apparent from the drawings. This results in the de-energization of the relays WP and CK as will be readily apparent and prevents any foreign currents from effecting such relays.

Upon the completion of the reverse operation of the track switch TS by the switch machine SM, the contacts 3 and 4 are operated to their reverse positions which closes a circuit from the positive terminal of the battery BT, through a circuit including contact 4 of the point detector contact mechanism PD in a reverse position, line wire 6, upper winding of relay WP, back contact l2 of relay CK, line wire 5, contact 3 of the point detector contact mechanism in a reverse position, to the negative terminal of the battery ET. The energy which flows in this circuit causes the relay WP to actuate its polar contacts to left hand positions and pick up its neutral contacts.

At thesarne time that energy is applied to the upper winding of the relay WP, it will be apparent that the relay CK receives energy from the line wires ii and 6; but, as the relay CK is slow acting, it requires agreater time for itscontacts S to be picked up than it does for the contacts of the relay WP to respond. Thus, upon the shift of the make-before-break contact l2 from a back to a front position, the energization of the relay WP is shifted from its upper pick-up winding to its lower stick winding.

This reverse stick circuit for the relay WP is closed from the positive terminal of the battery ET, through a circuit including contact 4 of the point detector contact mechanism PD in a reverse position, line wire 6, asymmetric unit [8, polar contact 7 of relay WP in a left hand position, lower winding of relay WP, polar contact 8 of relay WP in a left hand position, asymmetric unit l'i, front contact 9 of relay WP, front contact 912 of relay CK, line wire 5, contact 3 of the point to the negative terminal of the battery BT.

As the contact I! is of the make-before-break type, the energization of the relay WP is shifted 1 from its upper to its lower winding without interruption, so that the relay WP continues to be maintained through its reverse stick circuit. The signals may be selected through the circuits pr viously pointed out.

It will be noted that the current which flows in thi reverse stick circuit for the relay WP flows in the direction through the lower winding of the relay WP as the pick-up current flowed in tl upper winding of the relay WP. This means that the flux produced by the current flowing in each winding is in the same direction thereby causing substantially continuous flux to be present to maintain the relay picked up.

On the other hand, if the polar contacts of the relay WP do not respond, then the current flow through the lower winding of the relay WP upon the picking up of the contact l2 of the relay CK with the track switch TS in a reverse position is from left to right through the lower winding of relay WP which is in an opposite direction to the current flow which caused the initial picking up of the neutral contacts of this relay. Such reverse energization of the relay WP causes the magnetic flux in the relay to be reduced to zero and then build up in the opposite direction. As the flux of the relay passes through zero, the neutral contacts of the relay WP are forced down which immediately breaks such stick circuit at front contact 9 so that the neutral contacts of the relay WP remain dropped away. It will thus be seen that failure of the re ponse of the polar contacts causes the contact ID to remain open thereby preventing the clearing of a signal in the event that the polar contacts of the relay WP do not properly respond.

The operation of the system back to its normal condition is merely an inverse function of the operation already described and will therefore not be pointed out in detail as it will be readily apparent that the normal initial pick-up circuit for the relay WP with the relay CK de-energized causes current to flow from left to right in the upper winding of relay WP and that if the polar contacts 1 and 8 do not properly respond to such energization then the lower winding of relay WP will be energized from right to left upon the picking up of contact l2 thus causing the neutral contacts of relay WP to drop away as described for the reverse operation.

It may well be noted that this polarized cir-- cult for the control of relays WP and CK provides the usual protection inherent in such a polarized circuit, that any de-energization of the line ci cuit including the wires 5 and 5 causes the de-en ation of the relays WP and CK and also any .nting of the wires 5 and S will likewise cause the de-energization of the relays WP and OK. In other words, this circuit provides the usual protection of a polarized circuit, narne- 1y, that two breaks and two crosses must occur in order to improperly reverse the polarity thereon and cause a false energization of the relays WP and CK.

With reference to Fig. 2 of the accompanying drawings, the response of the polar contacts of the relay WP is ch cked in a similar manner as in Fig. 1, namely, by the comparison so to speak of the pick-up flux with the holding flux. In this form of the present inven "on, a local source of energy is employed instead of asymm t c units. Also, the relay WP is shown as picked up in series with the relay CK instead of in multiple with such relay as in Fig. 1.

The operation of this embod ment of the in vention may be adequately LllliilStnCd by merely conside 'ng the operation of the track swch from a mid-stroke position to normal posit n, for example, instead of cons deri g the whole sequence of events that may occur in operation from normal to reverse and. back again, such operation will be understood by analogy with that described in connection with that in Pig. 1.

Let us assume that the contacts 3 and 4 of the point detector contact mechanism PD are mid-stroke positions, then the relays CK and WP are shunted and de-energized. the actuation contacts 3 and 4 to normal p sitions, for example, the relays WP and CK areenergized in series by a circuit closed from. the posh tive terminal of the battery BT, through irrelay CK, upper winding of relay WP, 5, contact 4 of point detector contact mechanisin a normal position, to the negative terminal of battery BT. The current which flows in this circuit causes the polar contacts as well as the neutral contacts of the relay WP to immediately respond; but, as the relay CK is slow acting, its contacts do not respond until after a short period of time. When the contacts of the relay CK are picked up, the energization of the relay WP is shifted from its upper pick-up winding to its lower stick winding. With the polar contacts properly responded to the initial normal energization, a circuit is closed from (3+), through a circuit including polar contact 23 in a right hand position, front contact 22, front contact 2!, lower winding of relay WP, to (CN) It is noted that the direction of this current flow is from left to right in the lower winding of the relay WP which corresponds to the left to right direction of ourrent flow in the upper winding before the relay CK picked up. Thus, the relay WP will remain picked up so that the signal circuits can be selected in accordance with the proper position of the polar contacts in correspondence with the track switch TS.

If the polar contacts of the relay WP had not properly responded, then energy would be applied from (B) through polar contact 23 in a left hand position which would cause current flow in the lower winding of the relay WP from right to left in opposition to the direction of current fiow in the upper winding during the pick-up period. Such reversal of magnetic flux in the relay WP would cause the drop away of its contacts as pointed out in connection with Fig. 1,

and its contacts will remain dropped away by reason of opening of front contact 22.

It is to be noted that when the relay CK picks up, its contact 2% removes the upper winding of the relay WP from the line circuit and includes in place thereof a compensating resistor 24 which is preferably of the same resistance as the upper winding of the relay WP. This shift from the upper winding of the relay WP to the compensating resistor 24 does not effect any substantial change in the energizationof relay CK as the contact 25 is of the make-before-break type. It might also be noted in this connection, that the back contact 28 does not open the circuit for the er winding of the relay WP until the front cont is closed, although this need not be true if the timing characteristics of the relays be so chosen that the drop away period of the relay WP is greater than any lapse of time that might occur between the opening of back contact 2t and the closing of front contact 2!.

In both Figs. 1 and 2 the contacts of the relay WP will remain dropped away, if its polar contacts do not properly respond, until the track switch TS is unlocked and returned to its former position or to a new extreme position. This is obviously the operation, as the relay CK must be dropped away in order to close the initial pickup circuit for the relays WP in these two figures. However, an emergency release button EM as shown in Fig. 3 might also be inserted in series with the relay CK in each of these figures, although this is considered an unnecessary element in these figures because of the expected reliability of the relays employed in such circuits and upon an actual failure it would be desirable to impress such rigid operating characteristics as to enforce the changing out of the failing relay. In Fig. 3, the emergency release button EM is a preferable element of that form ofthe invention by reason of the operating characteristics which involve possible de-energizations of the relay WP'other than from the cause of failure inherent in the relay itself, as will be more readily apparent as the description progrosses.

With reference to Fig. 3 of the accompanying drawings, the response of the polar contacts of the relay WP is checked in a similar manner as in Figs. 1 and 2, namely, by the comparison so to speak of the pick-up flux with the holding'flux. In this form of the present invention, a local source of energy is employed instead of asymmetric units and the relay WP is picked up in series with the relay CK. The stick circuit for this embodiment of the invention is similar to Fig. 2 but also includes contacts on the switch machine control lever SML.

The operation of this embodiment of the invention may be adequately understood by considering the operation of the track switch from a midstroke position to a normal position and also from a midstroke position to a reverse position.

Let us assume that the contacts 3 and 4 of the point detector contact mechanism PD are in midstroke positions then the relays WP and CK are shunted as previously described. Upon the actuation of contacts 3 and t to normal positions, the relays WP and CK are energized in series by a circuit closed from the positive terminal of battery BT, through a circuit including contact 3 in a normal position, line wire 5, winding of relay CK, front contact of the emergency self-restoring push button EM, back contact of relay CK, upper winding of relay WP, line wire 6, contact 4 in a normal position, to the negative terminal of battery BT. The current which flows in this circuit causes the polar contacts to be actuated to right hand positions and the neutral contacts to be picked up, but as the relay CK is slow acting its contacts do not respond until after a short period of time.

When the contacts of the relay CK are picked up, the energization of the relay WP is shifted from its upper winding to its lower winding. With the polar contacts properly actuated by the initial pick-up energization, and with the switch machine lever SML in correspondence with the polar contacts and the track switch, a circuit is closed from (13+) through a circuit including contact of lever SML in a normal position, polar contact 33 of relay WP in a right hand position, front contact 32 of relay WP, front contact 3i of relay CK, lower winding of relay WP, to (CN). It is noted that the direction of this current flow is from left to right in the lower winding of the relay WP which corresponds to the left to right direction of current flow in the upper winding during the pick-up period for the relay WP. Thus, the relay WP will remain picked up so that the signal circuits can be selected in accordance with the proper position of the polar contacts in correspondence with the track switch TS.

, Let us assume that the contacts 3 and 4 of the point detector contact mechanism PD are operated from midstroke positions to reverse positions. Under these circumstances, energy flows from the positive terminal of battery BT through a circuit including contact 4 in a reverse position, line wire 6, upper winding of relay WP, back contact 3B of relay CK, front contact of the selfrestoring emergency push button EM, winding of relay CK, line wire 5, contact 3 in a reverse position, to the negative terminal of the battery BT.

After a time the contacts of the relay CK pick up opening the energizing circuit for the upper winding of the relay WP and shifting its own energizing circuit to the compensating resistor 24. Also, the picking up of relay CK closes the stick circuit for the lower winding of relay WP providing the polar contacts of the relay WP have properly responded and provided the switch machine control lever SML is in correspondence with the track switch TS. This stick circuit is closed from (B), through a circuit including contact 34 of lever SML in a reverse position, polar contact 33 of relay WP in a left hand position, front contact 32 of relay WP, front contact 3| of relay CK, lower winding of relay WP, to (CN). It is noted that the direction of this current flow is from right to left in the lower winding of relay WP, which direction corresponds to the direction of current flow in the upper winding of relay WP during its pick-up period for this operation. Thus, the relay WP will remain picked up so that the signal circuits can be selected in accordance with the proper position of the polar contacts in correspondence with the track switch TS and the switch machine lever SML.

t is noted that if the switch machine control lever SML is out of correspondence with the polar contacts of the relay WP then the stick circuit for such WP is not completed so that the relay WP fails to remain picked up upon the shift from its pick-up circuit to its stick circuit. Also, if the switch machine lever SML is operated to a new position while the relay CK is picked up, the relay WP is immediately dropped away. Should this condition occur and the track switch TS fail to respond to the control intended by the lever SML, then the lever SML may be returned to its former position and the relay WP again picked up by actuating the emergency push button EM for a sufiicient period to drop the relay CK away so as to momentarily establish the pick-up circuit for the relay WP subsequent to the release of the emergency push button EM.

It should be noted also that should the track switch TS and control lever SML be in corresponding positions but the polar contacts of the relay WP fail to properly respond, then the stick circuit is not completed and the relay WP drops away upon the picking up of the relay CK.

It might happen that the polar contacts of the relay WP and the lever contacts 34 and 35 should be in corresponding positions but out of correspondence with the track switch when the relay CK shifts the energization of the relay WP from its upper winding to its lower winding. Under such circumstances the direction of current flow is opposite in the lower winding to that established in the upper winding as pointed out in connection with Figs. 1 and 2 so that the contacts of relay WP immediately drop away and remain dropped away until proper conditions are established as will be readily apparent.

An indication system for a power operated track switch has thus been shown and described wherein the indicating relay WP not only indicates the position of the track switch, but also indicates the proper response of its polar contacts to the energy received over its polarized control circuit. Also one form of the present invention provides that the indicating relay WP has the added indication of correspondence between the track switch and its control lever included in its energized indicating condition.

Having thus described an indication system for railroad trafiic controlling systems as one specific embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

What I claim is:

1. In combination, a circuit at times energized with one polarity or the other, a checking relay slowly picked up whenever said circuit is energized irrespective of its polarity, a polar-neutral relay, a pick-up circuit for said polar-neutral relay energizable from said circuit when said checking relay is dropped away, and a stick circuit for said polar-neutral relay including its own neutral contact and energizable with one polarity or the other depending upon the position of its polar contacts when said checking relay is picked up.

2. In combination, a circuit at times energized with one polarity or the other, a checking relay slowly picked up whenever said circuit is energized irrespective of its polarity, a polar-neutral relay, a pick-up circuit for said polar-neutral relay energizable from said circuit when said checking relay is dropped away, a stick circuit for said polarmeutral relay including its own neutral contact and energizable from said circuit when said checking relay is picked up, and means including polar contacts on said polar-neutral relay and rectifier units for reversing the direction of current flow in said stick circuit dependent upon the positions of said polar contacts.

3. In combination, a circuit having positive or negative energy applied thereto, a slow-acting neutral relay connected in series in said circuit, a polar-neutral relay having two windings, a first circuit means for connecting one of said windings in multipie with said neutral relay when said neutral relay is de-energized, a second circuit means for connecting the other of said windings in multiple with said neutral relay when said neutral relay is picked up, said second circuit means including a rectifier, a front contact of said polarneutral relay and polar contacts of said polarneutral relay connected to determine the direction of current flow in said second winding dependent upon the positions of the polar contacts, and circuit selections made through contacts of said neutral and polar-neutral relays.

4. In combination; a circuit having positive or negative energy applied thereto; a slow-acting neutral relay connected in series in said circuit; a polar-neutral relay having two windings; circuit means for connecting one of said windings in series with said neutral relay only when said neutral relay is dropped away; circuit means for energizing the other of said windings from a local source, when said neutral relay is picked up, said circuit means including a front contact of said polar-neutral relay and polar contacts of said polar-neutral relay comiected to determine the direction of current flow in said second winding dependent upon their positions; and circuit selections made through contacts of said neutral and polar-neutral relays.

5. In combination, point detector contacts operated in accordance with the position and locked condition of a railroad track switch, a circuit energized with one polarity or the other depending upon the position of said point detector contacts, a polar-neutral relay picked up by the energy in said circuit, a control lever for governing the operation of the railroad track switch, means including the polar contacts of said polar-neutral relay for causing it to be dropped away after it is picked up if its polar contacts are out of correspondence with said control lever or are in positions opposite to those to which the pick-up energy should have actuated them, and signals having control circuits selected through polar and neutral contacts of said relay.

6. In combination, a circuit at times energized with one polarity or the other, a checking relay slowly picked whenever said circuit is energized irrespective of its polarity, a polar-neutral relay, a pick-up circuit for said polar-neutral relay energizable from said circuit when said checking relay is dropped away, a stick circuit for said polar-neutral relay including its own neutral contact and energizable with one polarity or the other depending upon the position of its polar contacts when said checking relay is picked up,

and othermeans for at times opening the enerizing circuit of said checking relay.

7. In combination, a circuit having positive or negative energy applied thereto, a slow-acting neutral relay connected in series in said circuit, a polar-neutral relay having two windings, circuit means for connecting one of said windings in series with said neutral relay only when said neutral relay is dropped away, circuit means for connecting the other of said windings in series with a local source only when said neutral relay is picked up, said circuit means including a front contact of said polar-neutral relay, polar contacts of said polar-neutral relay connected to determine the direction of current flow in said second winding dependent upon their positions, and circuit selections made through contacts of said neutral and polar-neutral relays.

8. In combination; a polarized circuit; a polarneutral relay having polar contacts, neutral contacts, a pickup circuit and a stick circuit; transfer means for at times shifting the control of said relay from its pick-up circuit to its stick circuit; means including said transfer means for supplying energy from said polarized circuit to said pick-up circuit; means including said transfer means for supplying energy from said polarized circuit to said stick circuit; and means including polar contacts on said relay for pole-changing said energy in said stick circuit.

9. In combination; a polarized circuit; a polarneutral relay having polar contacts, neutral contacts, a pick-up circuit and a stick circuit; transfer means dependent upon the energization of said polarized circuit for shifting the control of said relay from its pick-up circuit to its stick circuit; means including said transfer means for supplying energy from said polarized circuit to said pick-up circuit; means including said transfer means ior supplying energy fromsaid polarized circuit to said stick circuit; and means including polar contacts on said relay for polechanging said energy in said stick circuit.

10. In combination; a railway switch contact first winding, a second winding, neutral and polar contacts; means including said first winding for picking up said neutral contacts and for actuating said polar contacts to normal or reverse positionsin response to the normal or reverse energization respectively of said circuit; and means controlled over said circuit and including said neutral and said polar contacts for releasing said neutral contacts by energizing said second winding in opposing relation to the energization of said first winding when said polar contacts have failed to properly respond to the energization of said first winding. 7

11. In combination; a railway switch contact device; a circuit; means controlled by said device for energizing said circuit with current of normal or reverse polarity; an indication relay having a first winding, a second winding, neutral and polar contacts; means including said first winding for picking up said neutral contacts and for actuating said polar contacts to normal or reverse positions in response to the normal or reverse energization respectively of said circuit; and means controlled over said circuit and including said neutral and said polar contacts for sticking said neutral contacts by energizing said second winding in aiding relation to the energization of said first winding when said polar contacts have properly responded to the energization of said first winding.

12. In combination; a railway switch contact device; a circuit; means controlled by said device for energizing said circuit with current of normal or reverse polarity; an indication relay having a first winding, a second winding, neutral and polar contacts; means including said first winding for picking up said neutral contacts and for actuating said polar contacts to normal or reverse positions in response to the normal or reverse energization respectively of said circuit; means controlled by said neutral and said polar contacts for releasing said neutral contacts by energizing said second winding in opposing relation to the energization of said first winding when said polar contacts have failed to properly respond to the energization of said first winding; and means controlled over said circuit for transferring said circuit from said second winding to said first winding.

13. In combination; a polar-neutral relay having a pick-up winding and a stick winding; polar and neutral contacts on said relay; means for energizing said pick-up winding in normal or reverse directions for actuating said polar contacts to normal or reverse positions respectively and for picking up said neutral contacts; a plurality of rectifiers'; and means including said polar contacts, said neutral contacts and said rectifiers for energizing said stick winding in aiding relationship with said pick-up winding as determined by the position of said polar contacts when said polar contacts properly respond to the energization of said pick-up winding and for energizing said stick winding in opposing relationship with said pick-up winding as determined by the position of said polar contacts when said polar contacts fail to properly respond to the energization of said pick-up winding.

14. In combination, a polarized circuit energized with one polarity or the other and at times deenergized, a polar-neutral relay provided with polar and neutral contacts, relay means controlled over said circuit for momentarily allowing energy to be supplied from said circuit to said polar-neutral relay each time said circuit becomes energized, circuit means controlled by said relay means during the remaining time said circuit is energized to supply local energy to said polar-neutral relay in a direction depending upon the position of said polar contacts.

15. In combination, a polarized circuit, a polarneutral relay at times directly included in said circuit and provided with polar and neutral contacts responsive to the energy received from such circuit, asymmetric units, and stick circuit means including said polar contacts and said asymmetric units for causing the energy received from said circuit to at other times flow through said relay in a direction dependent upon the position of its polar contacts.

16. In combination; a power-operated railway track switch; a switch control lever for governing the power operation of said track switch; a circuit having positive or negative energy applied thereto in accordance with the position of said track switch; a slow acting neutral relay connected in series in said circuit; a polar-neutral relay having two windings; circuit means for connecting one of said windings in series with said neutral relay when said neutral relay is dropped away; circuit means for connecting the other of said windings in series with a local source when said neutral relay is picked up, said circuit means including a front contact of said polar-neutral relay, polar contacts of said polar-neutral relay and contacts of said switch control lever so connected as to allow current to flow in said second Winding in an aiding relationship with respect to the energization of said first winding only when said polar contacts and said switch control lever are in corresponding normal or reverse positions.

17. In combination, a polarized circuit energized with one polarity or the other and at times deenergized, a polar neutral relay having polar and neutral contacts, relay means controlled over said polarized circuit for momentarily allowing energy to be supplied from said circuit to said polar neutral relay each time said circuit becomes energized so as to pick up said polar-neutral relay, and a stick circuit means for said polar neutral relay energized in one direction or the other as determined by the polar positions assumed by said polar contacts, said stick circuit means being effective only when said polarized circuit is energized and said polar neutral relay is picked up.

18. In combination; point detector contacts operated to normal, reverse or mid-stroke posi-' tions when an associated track switch is in normal, reverse or unlocked positions respectively; an indication circuit; means for energizing said indication circuit with one polarity or the other depending upon the normal or reverse position of said point detector contacts and for deenergizing said circuit when said point detector contacts are in mid-stroke positions; a polar-neutral relay provided with polar and neutral contacts; relay means for momentarily allowing energy to be supplied from said circuit to said polar-neutral relay each time said circuit becomes energized with either polarity; rectifier means; stick circuit means including said rectifier means, said neutral and polar contacts, being efiectively energized during the time said circuit is energized so as to supply energy to said polar-neutral relay in a direction depending upon the position of. said polar contacts; and signals having control circuits selected through the polar and neutral contacts of said polar neutral relay; whereby the response of the polar contacts to the polarity of the current is checked in a manner to insure that the signals are selected in accordance with the actual position of the track switch as indicated by the point detector contacts.

FOREST B. HITCHCOCK. 

